The LOWER string function returns a character expression after converting uppercase character data to lowercase. The syntax of the LOWER string function is as follows:

LOWER ( < character_expression > )

The < character_expression > is an expression of character or binary data. < character_expression > can be a constant, variable or column and it must be of a data type that is implicitly convertible to VARCHAR; otherwise, the CAST function needs to explicitly convert < character_expression >.